Of recent times, it has become apparent that many pharmaceutical substances such as insulin, hormones, asthma treatments, lipophyllic drugs, opiates, erectile dysfunction medication, migraine medication or other therapeutic substances can be efficaciously delivered intranasally. This offers significant advantage, for example, where diabetics can intranasally receive insulin rather than subcutaneously by means of a needle.
This particular advantage is also provided for the use of hormone treatments amongst many other therapeutic substances. It is desired that a regular user can simply have provided an intranasal delivery device so that at any convenient time a dose of therapeutic substance can be taken. It will be appreciated that significantly less privacy is required to intranasally deliver a therapeutic substance as opposed to that required to inject the same substance via a syringe, and that hygiene requirements are reduced.
It is undesirable to expose a therapeutic substance user to the possibility of intranasally consuming more of the substance than is desired. BD Medical Pharmaceutical Systems of France offer for sale under the trademark ACCUSPRAY a nasal spray system which allows the delivery of therapeutic materials. The BD Medical Pharmaceutical Systems nasal spray pump is a syringe type device configured to receive a cartridge containing a single dose of a therapeutic substance. The intranasal spray device receives the cartridge longitudinally and the cartridge is configured to rupture adjacent an opening. The cartridge includes a plunger which is actuated by a secondary plunger on the nasal spray device so as to dispense the therapeutic goods by a plunging action and forcing the contents from the cartridge.
That is, a plunger is longitudinally moved to engage with a cartridge plunger which is linearly moved away from the direction the nasal spray is to be dispensed and is similar to a syringe in function, especially dental syringes configured to receive cartridges of oral anaesthetic. In a dental syringe, the contents of the cartridge are plunged from one end longitudinally and out the other. The BD Medical Pharmaceutical Systems device plunges from one end longitudinally and the contents are forced out the same end through an aperture in the plunger.
A significant disadvantage with this development resides in the single use of the cartridges whereby once the plunger has been plunged it cannot be removed to be re-plunged to allow any unused or undispensed therapeutic goods to be dispensed.
In another attempt at providing a single dose nasal spray system, U.S. Pat. No. 6,948,492 (Wermeling et al) discloses the use of an apparatus for the self-administration of liquid pharmaceutical compositions intranasally. In this patent, a body is configured to contain a plurality of radially extending and circumferentially spaced apart vials each containing a single dose of a therapeutic substance. Each of the vials is sealed in a housing which is electronically controlled to allow rotation of a body cover at predetermined intervals to expose the opening of one of the vials. Each vial includes a plunger having a fluid channel disposed substantially longitudinally through the centre thereof. The channel is configured to receive a needle tip extending from a lower end of a nasal applicator head.
In use, once a vial has been exposed at a predetermined time, the nasal spray applicator head is engaged with the housing so that the needle is received within the fluid channel of the plunger. Movement of the applicator head downwardly toward the bottom of the vial causes the contents of the vial to be plunged through the needle running through the fluid channel and out an aligned channel in the nasal applicator which is configured to be disposed in or adjacent a user's nose.
The lower end of the plunger in each vial includes a recess to receive the nasal spray applicator needle so that once the plunger is fully moved to the bottom of the vial, the needle does not engage with the bottom of the vial so as not to damage the needle or the bottom of the vial.
Unfortunately, the electronic control of this device means that a user needs to wait a predetermined time before being able to access another vial containing therapeutic materials. In the case of a diabetic, for example, this may be particularly undesirable as usage of insulin is not necessarily a function of elapsed time between a previous dose. Furthermore, the use of the needle on the lower end of the nasal applicator is disadvantageous so far as the needle tip is exposed to contamination when removing it from one vial and engaging it with another vial. Yet further, the plunger needs to be made to relatively high tolerances to avoid the needle extending deeper than the plunger when fully plunged.
It will be appreciated that the recess provided to receive the needle tip at the bottom end of the plunger disadvantageously retains some contents of the vial due to its intrinsic nature. Unfortunately, it is not possible to re-actuate the nasal sprayer of either this US patent or the BD Medical Pharmaceutical Systems device by replunging the vial so that any contents that remain cannot be dispensed.
Both the BD Medical Pharmaceutical Systems nasal device and the Wermeling et al device require specialised manufacturing techniques and components to effect these single dose nasal sprayers. Furthermore, it will be appreciated that different sized doses of therapeutic substances cannot be accommodated in either of the prior art nasal sprayers. For example, the Wermeling et al disclosure is limited by the configuration and size available to receive a vial within the housing and the BD Medical Pharmaceutical Systems device can also only take a particular sized dose. It is therefore the case that in order to dispense a plurality of different sized doses, different sized intranasal dispensing apparatus would be required accordingly. This is disadvantageous insofar as it unnecessarily adds to costs in providing different devices for different sized doses.